49ers’ McGlinchey and Falcons’ Ryan — two big men...

1of3Mike McGlinchey (far right, back row) and Matt Ryan (center, back) on the day Ryan was drafted No. 3 overall in the 2008 NFL draft.Photo: McGlinchey family

2of3Mike McGlinchey (69) reacts to fans as he leaves the field after the San Francisco 49ers defeated the Green Bay Packers 37-8 at Levi’s Stadium on Nov. 24.Photo: Carlos Avila Gonzalez / The Chronicle

3of3The Falcons’ Matt Ryan warms up prior to a Nov. 28 game against the New Orleans Saints.Photo: Carmen Mandato / Getty Images

They are first cousins who went to the same high school, attended private Catholic colleges, were top-10 NFL draft picks and share eerily similar personalities.

And this week, Falcons quarterback Matt Ryan, 6-foot-4 and 217 pounds, is grateful he has something else in common with 49ers right tackle, Mike McGlinchey, who is 6-8 and 315 pounds: They both play offense.

“I’m glad I don’t have to go against him on the field, actually,” Ryan said to Atlanta reporters. “… That wouldn’t be fun to get hit by him.”

Given their age difference, Ryan, 34, and McGlinchey, 24, weren’t teammates or opponents in organized sports growing up. But that will change Sunday when Atlanta visits the 49ers at Levi’s Stadium.

McGlinchey — who has 24 first cousins — has an uncle, brother and seven other cousins who have played college football, meaning his massive extended family has spent seemingly half its lives in stadiums.

However, it will be different when about 30 relatives of McGlinchey and Ryan settle into their seats Sunday.

Ryan, the No. 3 pick in 2008 from Boston College, is a four-time Pro Bowler who was the 2016 NFL MVP and is one of 10 quarterbacks in history with 50,000 career passing yards.

And he’s been a longtime influence on McGlinchey.

In elementary school, McGlinchey attended many of his cousin’s games at Boston College and he was at the NFL Draft in New York when Ryan was selected. On a more personal level, their families — Janet McGlinchey and Ryan’s mother, Bernie, are sisters — are among a large group of relatives that’s gathered each summer for extended vacations in North Wildwood, N.J.

“I know that when I was a kid all I ever tried to do was be like Matt in every way that I could in football,” McGlinchey said. “I’d watch his interviews. I’d watch everything about Matt. I don’t know, maybe I just adopted the way that he did things because he always did it the right way.”

McGlinchey evidently took exceptional notes. This week, 49ers head coach Kyle Shanahan said McGlinchey and Ryan were “almost like the same guy.”

At the 2018 combine, Shanahan, who was Ryan’s offensive coordinator in Atlanta in 2015 and ‘16, was aware Ryan had a cousin in that year’s draft. And he quickly figured out who it was when McGlinchey met the 49ers for an interview in Indianapolis.

“Just the way he came in and introduced himself to everyone in the room, the way he sat down and talked, right then I was like ‘Man, this guy reminds me of Matt Ryan,’” Shanahan said. “Then I looked down at my notes that we get from everyone and it says it’s his cousin.

“I always joke with him — they’re both CEOs. Right when they walk in a room they know everyone’s name, they know how to handle themselves. … They come from good families, they’ve been raised the right way and they both love football. They are both extremely intense.”

Ryan and McGlinchey, last year’s No. 9 pick from Notre Dame, both attended William Penn Charter High in Philadelphia.

However, Ryan figured his baby cousin might have a future in football long before he reached high school. McGlinchey weighed 10 pounds, 6 ounces at birth.

“He was always a monster,” Ryan said. “He was always a big kid. I remember as a baby you’d be like, ‘God, this kid is big, you know?’ But he’s super athletic for an offensive lineman. He was always a freak.”

McGlinchey relishes discussing the day Ryan learned he was all grown up.

At a high school graduation party for a cousin, McGlinchey, who had just finished 10th grade, was part of a three-on-three driveway basketball game that included Ryan, then an established multi-millionaire NFL quarterback.

Ryan’s brother, Mike, tossed McGlinchey an alley-oop and …

“Matt went up to defend it and I caught it two-handed and put it down on him,” McGlinchey said. “That kind of turned some heads at the party a little bit. Which was a cool moment for me because I think at that point I was still a little kid to Matt.

“It’s something that I’ll probably always remember. And probably always give him a little s— for. … I took it down on a professional athlete at the time. It was pretty good.”

McGlinchey said Ryan later responded with an elbow to his chin as payback. He was joking. Probably.

McGlinchey noted he has plenty of relatives besides Ryan who share their hyper-competitive gene. Once, McGlinchey and a collection of cousins played a tackle-football game … in suits … at McGlinchey’s grandmother’s wake.

“There were always elbows being thrown,” McGlinchey said of their various pick-up games. “There were people being shoved all over. It used to be a lot more when we were in grade school and high school, but that whole competitive spirit is what my family was kind of built off of.”

McGlinchey, the oldest of six children that includes four other brothers, is one of several towering figures in his immediate family, which includes several other linemen. Meanwhile, his uncle and many of his cousins have been quarterbacks.

So Ryan isn’t alone in being grateful he won’t have to battle directly against his industrial-sized baby cousin Sunday. Janet McGlinchey feels the same way.

“My sisters were always cringing that their kids would get hurt when they were playing together,” she said. “I was different. I was always cringing that my kids would hurt them.”

Eric Branch has worked at the San Francisco Chronicle since 2011 as the 49ers beat writer. Before that, he covered the 49ers for the Santa Rosa Press Democrat in 2010. Since he began his career in journalism in 1997 in Logansport, Ind., he’s covered events ranging from archery tournaments to the NCAA Men’s Basketball Tournament.